Modern aircraft are equipped with extensive sensing and self diagnostic capabilities that produce digital data and computer-generated messages that are used by the flight crew and the aircraft's flight and engine control systems to operate the aircraft. This data is also useful for post-flight analysis and is therefore stored on electronic devices commonly referred to as Flight Data Recorders (FDRs), including a category of FDR called the quick access recorder (QAR).
Most commercial aircraft and many military aircraft have a regulatory requirement to record flight data on a Flight Data Recorder (FDR). The flight data stored in the FDR can be used to retrospectively evaluate flight operations and also try to determine the cause of an abnormal flight condition or an accident. In all cases, the retrieval of stored FDR data occurs only after the completion of a flight by means of a physical connection to or removal of recording media from the FDR (or QAR), or short range wireless data transmission. When an accident occurs, an investigation team attempts to recover the FDR and analyze the flight data stored in the FDR. The data recorded to the FDR is meant to be sufficient to allow recreation of the events that preceded the accident. However, in some cases, the FDR may be physically damaged, causing the recorded flight data to be irretrievable from the FDR. If the aircraft has crashed in an inaccessible location, such as in a large body of water or in a remote land region, or if the aircraft has disintegrated during the crash, the physical FDR may not be locatable or retrievable. If the FDR has been damaged to the extent that flight data cannot be retrieved from the FDR, or if the FDR itself cannot be located, accident investigators are left with no flight data with which to understand the circumstances surrounding the accident.
Since the data stored on the physical FDR is only available after physically retrieving the device or its data storage elements after a flight, it is therefore of no value for analysis, associated crew guidance, and emergency response planning while the aircraft is still in flight.
In commonly owned U.S. Pat. No. 7,206,630, a flight data transmission system is described which allows for flight data acquisition in the ordinary course of events. Flight data is formatted and incorporated into an email, which is transmitted using a communication system, such as a satellite modem. There is no provision however for data accumulation and transmission in an emergency situation or where more detailed data related to specific time periods is desired.